1. Technical Field
Embodiments of the present invention relate to a liquid ejecting head, which ejects a liquid from a nozzle opening, and a liquid ejecting apparatus. In particular, embodiments of the invention relate to an ink jet recording head, which discharges a liquid such as ink, and an ink jet recording apparatus.
2. Related Art
The ink jet recording head, which is an example of the liquid ejecting head, discharges ink droplets from a nozzle opening onto an ejecting target medium. Ink adhering to the vicinity of the nozzle opening of a liquid ejecting surface and ink that has solidified in the vicinity of the nozzle opening can cause problems such as the discharge direction of the ink droplets being unstable and poor discharging such as the ink droplets not being discharged.
A liquid ejecting apparatus has been proposed that cleans ink, fluff, dust, paper dust or the like, which has adhered to the liquid ejecting surface, by wiping the liquid ejecting surface using a wiper blade such as a rubber plate (for example, refer to JP-A-2010-228151).
In addition, even if the liquid ejecting surface is wiped using the wiper blade, the ink, fluff, dust, paper dust or the like remains adhered to the surface of a protective member such as a cover head, which is provided on the liquid ejecting surface side. As a result, the ejecting target medium becomes dirty when the ejecting target medium or the like makes contact with the protective member. Therefore, an ink jet recording apparatus has been proposed in which a concave portion is provided between the protective member and the liquid ejecting surface, and the surface of the protective member and the liquid ejecting surface are cleaned using the wiper blade (for example, refer to JP-A-2004-82699).
However, when the level difference between the liquid ejecting surface of the nozzle plate and the surface of the protective member is too great, unwiped material remains when the wiper blade wipes the surface of the protective member and the liquid ejecting surface.
In addition, when the liquid ejecting surface of the nozzle plate and the surface of the protective member have the same height, that is, there is no level difference therebetween, the ejecting target medium is likely to make contact with the nozzle plate. There is a concern that problems such as jamming of the ejecting target medium, deformation of the nozzle plate, and exfoliation of the nozzle plate may be caused by the ejecting target medium contacting the nozzle plate.
Therefore, there is a great demand to appropriately adjust the level difference between the liquid ejecting surface of the nozzle plate and the surface of the protective member based on the properties of the ink jet recording head and the properties of the wiper blade.
Meanwhile, because the thickness of the nozzle plate and the thickness of the protective member are related to the discharge properties of the ink droplets, the strength, the shape and the like required from the nozzle plate and the protective member themselves, the thicknesses for an optimal level difference and the thicknesses required from the nozzle plate and the protective member themselves are in conflict. Also, there are restrictions to the manner in which the level difference can be adjusted.
Furthermore, this problem is present not only in an ink jet recording head, but also in a liquid ejecting head that ejects a liquid other than an ink.